"Groupthink is a deterioration of mental efficiency, reality testing, and moral judgment that results from in-group pressures."

Irving Janus, 1972

Perceived intergroup competition

Social identity theory

Social judgment

Group-based social hierarchy

Group attribution error

Deindividuation

Group polarization

Integrative theory of intergroup conflict

Perceived group competition

Social comparison

Upward social comparison

Downward social comparison

Group Influence

People change their behavior or attitudes to match those of the group they identify with or seek to belong to. Group members often prematurely seek consensus, influencing decisions and actions.

Group Polarization

The original attitudes of individuals become exaggerated when shared by others. Group members can fuel each other’s sense of superiority, dislike for adversaries and outrage at any perceived threat. In extreme cases, this exaggerated polarization can lead to group frenzy and mob behavior.

In-Group Bias

Identification with a group makes individuals unduly subject to being influenced by the biases, loyalties, and values of the group. Embedding reporters with troops during a war builds ties of loyalty and identification that make it almost impossible for them to report in an impartial or comprehensive way.

Group Projection

Each “side” projects traits onto the groups that it sees as allies or foes. Two polarized sides call each other biased and extreme. Each may truly believe that the other is being unreasonable. Semantics can blur the line. Freedom fighter or violent rebel? Terrorist or soldier? Fanatic or martyr?

Bandwagon effect

Tendency to do (or believe) things because many other people do (or believe) the same. Related to groupthink, herd behavior and conformity.